Cassano has been a key player for his country since the arrival of Cesare Prandelli as Coach, but his place at Euro 2012 is now in doubt.
"Dear Antonio, life has thrown at you another important test," the Juventus custodian told Sky Sport Italia.
"I'm convinced that you'll face it in the best possible manner because you like challenges.
"You have the right irony, the right happiness and the right strength - thanks to your family - to come out of this.
"We here will all be waiting for you with our arms open because we know that you could be our added weapon for the European Championship."